Xconomy -- Antibodies that can zero in on specific diseased cells are some of biggest-selling and fastest-growing fields in all of biotech. Yet after three decades of R&D, if you talk to people who try to discover these things, they’ll tell you it’s a long and risky slog to get any good candidates for clinical trials. San Francisco-based Ablexis is betting that it has created a more effective way to generate promising antibodies, and revamped its business model to try to generate real cash.